1. Field of the Invention
This invention relates to a fiber composition, more particularly to a fiber composition including a fiber modifier containing a blend of maleic anhydride and a copolymer component.
2. Description of the Related Art
Disposable hygienic absorbent products, such as disposable diapers, generally include a liquid-permeable surface layer, a liquid-impermeable backsheet, and an absorbent layer interposed between the liquid-permeable surface layer and the liquid-impermeable backsheet. The absorbent layer is typically made from an absorbent material that includes natural fibers such as cellulose fluff pulp fibers, cotton fibers, and rayon fibers, and a super absorbent polymer (SAP). After water is absorbed into the absorbent layer, the absorbent material of the absorbent layer tends to expand and become heavy, and results in an uncomfortable feeling. Thus, in addition to the absorbent material, synthetic fibers are incorporated into the absorbent layer so as to form a supportive structure to fix the absorbent material in place.
The synthetic fibers traditionally used for formation of the supportive structure are thermo-bondable bi-component fibers made from polyolefins, polyesters or combinations thereof. Since these traditional thermo-bondable bi-component fibers have a poor thermo-bonding affinity for the natural fibers, the supportive structure formed by these traditional thermo-bondable bi-component fibers is unable to effectively fix the absorbent material in place. In order to improve adhesion between the thermo-bondable bi-component fibers and the natural fibers, a bi-component fiber disclosed in U.S. Pat. No. 5,981,410 (hereinafter referred to as the '410 patent) has been widely used in the market place. Particularly, in the Examples of the '410 parent, the core component of the bi-component fiber is made from polypropylene, and the sheath component of the bi-component fiber includes non-grafted polyethylene and polyethylene grafted with maleic anhydride. The maleic anhydride is used as a modifier for improving the thermo-bonding affinity of the bi-component fiber to natural fibers.